OBJECTIVETo investigate the protective effect of heat shock protein 70 (HSP70) against hypoxic pulmonary hypertension (HPH) in neonatal rats.

METHODSA total of 128 neonatal rats were randomly divided into blank control group, HPH model group, empty virus group, and HSP70 group, with 32 rats in each group. Before the establishment of an HPH model, the rats in the blank control group and HPH model group were given caudal vein injection of 5 μL sterile saline, those in the empty virus group were given caudal vein injection of 5 μL Ad-GFP (1 010 PFU/mL), and those in the HSP70 group were given caudal vein injection of 5 μL Ad-HSP70 (1 010 PFU/mL). HPH model was prepared in the HPH model, empty virus, and HSP70 groups after transfection. At 3, 7, 10, and 14 days after model establishment, a multi-channel physiological recorder was used to record mean pulmonary arterial pressure (mPAP), optical and electron microscopes were used to observe the structure and remodeling parameters of pulmonary vessels, and Western blot was used to measure the protein expression of HSP70, hypoxia-inducible factor-1α (HIF-1α), endothelin-1 (ET-1), and inducible nitric oxide synthase (iNOS) in lung tissues.

RESULTSAt 3, 7, 10, and 14 days after model establishment, the HPH model group and the empty virus group had a significantly higher mPAP than the blank control group (P<0.05). On days 7 and 10 of hypoxia, the blank control group and the HSP70 group had significantly lower MA% and MT% than the HPH model group and the empty virus group (P<0.01); on day 14 of hypoxia, the HPH model group, empty virus group, and HSP70 group had similar MA% and MT% (P>0.05), but had significantly higher MA% and MT% than the blank control group (P<0.01). On days 3, 7 and 10 of hypoxia, the HSP70 group had significantly higher protein expression of HSP70 than the HPH model group, empty virus group, and blank control group (P<0.01); the HSP70 group had significantly lower expression of HIF-1α, ET-1, and iNOS than the HPH model group and the empty virus group (P<0.05) and similar expression of HIF-1α, ET-1, and iNOS as the blank control group (P>0.05).

CONCLUSIONSIn neonatal rats with HPH, HSP70 transfection can increase the expression of HSP70 in lung tissues, downregulate the expression of HIF-1α, ET-1, and iNOS, alleviate pulmonary vascular remodeling, and reduce pulmonary artery pressure; therefore, it may become a new strategy for the treatment of HPH in neonates.